(19)

(11)

EP 0 972 252 A1

(12)

(43) Date of publication: 19.01.2000 Bulletin 2000/03 (21) Application number: 98911981.3 (22) Date of filing: 23.03.1998

(51) International Patent Classification (IPC)7: G06F 15/18 (86) International application number: PCT/US9805/736 (87) International publication number: WO 9844/428 (08.10.1998 Gazette 1998/40)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 01.04.1997 GB 9706521 (71) Applicant: PORTA SYSTEMS CORPORATION Syosset, NY 11791 (US)	(72) Inventors: AUSTIN, James East Yorkshire Y025 9LY (GB) ZHOU, Ping Heslington York Y01 5DD (GB) (74) Representative: Skone James, Robert Edmund et al GILL JENNINGS & EVERYBroadgate House7 Eldon Street London EC2M 7LH London EC2M 7LH (GB)